Torque limiting clutch

An overload clutch comprising a driving part, a driven part, a cage, means mounting said parts and cage for relative rotation and each of said parts having at least one torque transmtting abutment, a rolling element disposed between said parts and guided by said cage, biasing means to bias axially said element into torque transmitting engagement with said torque transmitting abutments of said parts when said clutch is engaged, said rolling element being movable out of engagement with said torque transmitting abutments to disengage the clutch on application of a torque exceeding a predetermined torque to one of said parts, a recess in one of said parts to accommodate said element when the clutch is disengaged, a spacer, movable by said cage into spacing relationship with said parts on disengagement of the clutch, wherein said clutch can be disengaged by relative rotation between said part in either direction and said clutch can be re-engaged by relative rotation between said parts in the opposite direction to that which caused disengagement, said clutch including two pairs of interengageable abutments, one abutment of each pair being provided on the cage and the other on the other of said parts and operable to cause said cage and said other of said parts to rotate together, one pair of abutments being operable on relative rotation between the clutch parts in the opposite direction to that in which the other pair is operable, biasing means normally to bias one abutment of each pair in a direction towards engagement with the other abutment of the pair, first control means being provided on said one clutch part;

• (a) to prevent interengagement of said abutments of one pair when said clutch is disengaged as a result of relative rotation in one direction whilst permitting interengagement of said abutments of the other pair on resetting by relative rotation in the reverse direction to said one direction;
• and
• (b) to prevent interengagement of said abutments of the other pair when said clutch is disengaged as result of relative rotation in the opposite direction to said one direction whilst permitting interengagement of the abutments of said one pair on resetting by relative rotation in the reverse direction to said other direction
• and second control means to maintain said abutments of both pairs out of interengagement during the initial stages of disengagement of said clutch.